What type RCD for energy saving lights?

[ericmark]

That would not be true if one accepts and extrapolates from the implication of the boiler instructions above (that "energy efficient equipment" can generate DC fault currents) and one wants the RCD to satisfactorily protect the one appliance that it is meant to be protecting.

Kind Regards, John

I may have 14 RCD's but many only have 2, so any item which which stops them working is rather serious.

 

[JohnW2]

I may have 14 RCD's but many only have 2, so any item which which stops them working is rather serious.

That's obviously true. However, as I said, and contrary to what you were suggesting, even if every appliance was on a dedicated circuit with its own RCD, it's possible that an appliance/circuit would not be satisfactorily protected if the RCD was of 'the wrong type'.

However, I remain unconvinced that any of this is necessarily a significant issue in a domestic installation. However, I'm certainly open to 'being convinced' - but no-one has as yet been able to direct me to any particularly useful information.

Kind Regards, John

 

[ericmark]

I think I will replace the front of house sockets RCBO, at £16 that is cheap enough, but the original question remains, if one moves from tungsten to either fluorescent or LED will the type AC RCD still protect? To be frank in my house since the RCD only supplies lights, and in real terms lights don't really need RCD protection, it is not really an issue.

But where a common RCD feeds many sub circuits could the use of fluorescent or LED lights stop the RCD tripping with a faulty item plugged into a socket? I think there is a clue in the name LED that there is some rectifying likely, so could produce DC as the D in LED does stand for diode. But can it produce enough DC to cause a problem?

 

[JohnW2]

I think I will replace the front of house sockets RCBO, at £16 that is cheap enough, but the original question remains, if one moves from tungsten to either fluorescent or LED will the type AC RCD still protect? To be frank in my house since the RCD only supplies lights, and in real terms lights don't really need RCD protection, it is not really an issue.

As you say, I would personally think that it's probably a non-issue. Quite apart from my uncertainty about whether any of this business is a significant issue in relation to a domestic installation, as you say, conceivable malfunction of RCD protection of a lighting circuit is hardly something to loose sleep about.

But where a common RCD feeds many sub circuits could the use of fluorescent or LED lights stop the RCD tripping with a faulty item plugged into a socket?

That's the question - about which we have yet to find any definitive information - but, as above, I would personally very much doubt that LED lights (or anything much else in a domestic environment) would significantly impair the funbctioning of a Type AC RCD.

I think there is a clue in the name LED that there is some rectifying likely, so could produce DC as the D in LED does stand for diode. But can it produce enough DC to cause a problem?

I think that even the cheapest and nastiest of LED lamps/bulbs I've dissected have had full-wave rectification (i.e. a bridge rectifier), so I doubt that there would be a significant, if any, DC component - and, as above, doubt even more that there could be enough of a DC component to represent any problem.

Kind Regards, John

 

[ericmark]

On another forum I was alerted to this report which in conclusion says

RCD's are unlikely to be adversely affected (i.e. prevent tripping under a fault condition) by the presence of dc arising from inverters used in conjunction with embedded generation plant, nor is there any evidence to suggest any increased safety risk. The issue of nuisance tripping i.e. tripping not under fault conditions, whilst being an inherently safe option, may never the less become more of an issue and should be investigated.

See 5.1 page 27 this 2005 report seems to say no problem which is why likely type AC not banned in UK. So who do we believe?

 

[JohnW2]

On another forum I was alerted to this report which in conclusion says See 5.1 page 27 this 2005 report seems to say no problem which is why likely type AC not banned in UK. So who do we believe?

Who knows - as I've said, there seems to be a paucity of readily-available useful information, let alone data.

As I also said, because of that paucity of information, I am yet to be convinced that this is a significant issue, particularly in domestic environments. However, as we've been told, it appears that ('rightly or wrongly') a number of countries have actually 'banned' Type AC RCDs, so there could well be a lot that I am so far missing.

Kind Regards, John